7 Theories on the Origin of Life (2022)

7 Theories on the Origin of Life (1)

Jump to:

  • An electric spark
  • Molecules of life met on clay
  • Deep-sea vents
  • Born from ice
  • Understanding DNA
  • Simple beginnings
  • Life came from space
  • Additional resources
  • Bibliography

The origin of life on Earth began more than 3 billion years ago, evolving from the most basic of microbes into a dazzling array of complexity over time. But how did the first organisms on the only known home to life in the universe develop from the primordial soup?

Science remains undecided and conflicted as to the exact origin of life, also known as abiogenesis. Even the very definition of life is contested and rewritten, with one study published in the Journal of Biomolecular Structure and Dynamics (opens in new tab), suggesting uncovering 123 different published definitions.

Although science still seems unsure, here are some of the many different scientific theories on the origin of life on Earth.

It started with an electric spark

7 Theories on the Origin of Life (2)

(Video) 7 Theories for Origins of life | How life started on earth

Lightning may have provided the spark needed for life to begin.Electric sparks can generate amino acids and sugars from an atmosphere loaded with water, methane, ammonia and hydrogen, as was shown in the famous Miller-Urey experiment in 1952, according to Scientific American (opens in new tab). The experiment's findings suggested that lightning might have helped create the key building blocks of life on Earth in its early days. Over millions of years, larger and more complex molecules could form.

Although research since then has revealed the early atmosphere of Earth was actually hydrogen-poor, scientists have suggested that volcanic clouds in the early atmosphere might have held methane, ammonia and hydrogen and been filled with lightning as well, according to the University of California (opens in new tab)

Molecules of life met on clay

The first molecules of life might have met on clay, according to an idea elaborated by organic chemist Alexander Graham Cairns-Smith at the University of Glasgow in Scotland. Cairns-Smith proposed in his 1985 controversial book “Seven Clues to the Origin of Life'' (opens in new tab), that clay crystals preserve their structure as they grow and stick together to form areas exposed to different environments and trap other molecules along the way and organise them into patterns much like our genes do now.

Related Links

What is the difference between prokaryotic and eukaryotic cells?

What is biology?

What are bacteria?

(Video) 7 Theories on the Origin of Life

What is an amoeba?

Is there water on Mars?

The main role of DNA is to store information on how other molecules should be arranged. Genetic sequences in DNA are essentially instructions on how amino acids should be arranged in proteins. Cairns-Smith suggests that mineral crystals in clay could have arranged organic molecules into organized patterns. After a while, organic molecules took over this job and organized themselves.

Although Cairns-Smith's theory certainly gave scientists food for thought in the 1980s, it has still not been widely accepted by the scientific community.

Life began at deep-sea vents

7 Theories on the Origin of Life (3)

The deep-sea vent theory suggests that life may have begun at submarine hydrothermal vents spewing elements key to life, such as carbon and hydrogen-, according to the journal Nature Reviews Microbiology (opens in new tab).

Hydrothermal vents can be found in the darkest depths of the ocean floors, typically on diverging continental plates, according to the Natural History Museum (opens in new tab). These vents erupt fluid which is superheated by the Earth’s core as it passes up through the crust, before being ejected at the vets. During its journey through the crust it collects dissolved gases and minerals, such as carbon and hydrogen.

Their rocky nooks could then have concentrated these molecules together and provided mineral catalysts for critical reactions. Even now, these vents, rich in chemical and thermal energy, sustain vibrant ecosystems.

Abiogenesis by way of hydrothermal vents continues to be investigated as a plausible cause of life on Earth. In 2019, scientists at University College London (opens in new tab), successfully created protocells (non-living structures that help scientists understand the origins of life) under similar hot, alkaline environmental conditions to hydrothermal vents.

Life had a chilly start

Ice might have covered the oceans 3 billion years ago and facilitated the birth of life. "Key organic compounds thought to be important in the origin of life are more stable at lower temperatures,” Jeffrey Bada at the University of California, told New Scientist (opens in new tab). At normal temperatures these compounds, such as simple sets of amino acids, are sparsely populated in water, but when frozen become concentrated and facilitate the emergence of life, according to Bada’s work published in the journal Icarus (opens in new tab).

(Video) 7 theories on the origin of life

Ice also might have protected fragile organic compounds in the water below from ultraviolet light and destruction from cosmic impacts. The cold might have also helped these molecules to survive longer, enabling key reactions to happen.

The answer lies in understanding DNA formation

7 Theories on the Origin of Life (4)

Nowadays DNA needs proteins in order to form, and proteins require DNA to form, so how could these have formed without each other? The answer may be RNA, which can store information like DNA, serve as an enzyme like proteins, and help create both DNA and proteins, according to the journal Molecular Biology of the Cell (opens in new tab). Later DNA and proteins succeeded this "RNA world," because they are more efficient.

RNA still exists and performs several functions in organisms, including acting as an on-off switch for some genes. The question still remains how RNA got here in the first place. Some scientists think the molecule could have spontaneously arisen on Earth, while others say that was very unlikely to have happened.

Life had simple beginnings

Instead of developing from complex molecules such as RNA, life might have begun with smaller molecules interacting with each other in cycles of reactions. These might have been contained in simple capsules akin to cell membranes, and over time more complex molecules that performed these reactions better than the smaller ones could have evolved, scenarios dubbed "metabolism-first" models, as opposed to the "gene-first" model of the "RNA world" hypothesis.

Life was brought here from elsewhere in space

7 Theories on the Origin of Life (5)

Perhaps life did not begin on Earth at all, but was brought here from elsewhere in space, a notion known as panspermia, according to NASA (opens in new tab). For instance, rocks regularly get blasted off Mars by cosmic impacts, and a number of Martian meteorites have been found on Earth that some researchers have controversially suggested brought microbes over here, potentially making us all Martians originally. Other scientists have even suggested that life might have hitchhiked on comets from other star systems. However, even if this concept were true, the question of how life began on Earth would then only change to how life began elsewhere in space.

Additional resources

For more information into the theories of life’s origins check out “The Stairway To Life: An Origin-Of-Life Reality Check (opens in new tab)” by Change Laura Tan and “The Mystery of Life's Origin (opens in new tab)” by Charles B. Thaxton, et al.

Bibliography

Matthew Levy et al, “Prebiotic Synthesis of Adenine and Amino Acids Under Europa-like Conditions”, Icarus, Volume 145, June 2000, https://doi.org/10.1006/icar.2000.6365 (opens in new tab)

(Video) 7 theories on the Origin of Life

William Martin, “Hydrothermal vents and the origin of life”, Nature Reviews Microbiology, Volume 6, September 2008, https://doi.org/10.1038/nrmicro1991 (opens in new tab)

K. A. Dill and L. Agozzino, “Driving forces in the origins of life”, Open biology, Volume 11, February 2021, ttps://doi.org/10.1098/rsob.200324 (opens in new tab)

Ben K. D. Pearce et al, “Origin of the RNA world: The fate of nucleobases in warm little ponds”, PNAS, Volume 114, October 2017, https://doi.org/10.1073/pnas.1710339114 (opens in new tab)

7 Theories on the Origin of Life (6)

Charles Q. Choi

Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.

FAQs

What are the main theories of the origin of life? ›

The Oparin and Haldane theory is known as biochemical theory for the origin of life. According to the Oparin-Haldane model, life could have arisen through a series of organic chemical reactions that produced ever more complex biochemical structures.

Which theory of origin of life is most acceptable? ›

The most accepted theory on the origin of life, is the theory of biochemical evolution.

What is theory short answer? ›

A theory is a well-substantiated explanation of an aspect of the natural world that can incorporate laws, hypotheses and facts. The theory of gravitation, for instance, explains why apples fall from trees and astronauts float in space.

How many theories are there for origin of life? ›

7 theories on the origin of life.

What is most important for origin of life? ›

So the correct option is ' Carbon'.

Why is it important to study the origin of life? ›

Earth will always be the most accessible habitable planet for study. Consequently, studying the origin and earliest evolution of life, along with the long-term evolution of the Earth's environments, helps us understand why the Earth became habitable and why terrestrial life has persisted for billions of years.

How will you explain the origin and evolution of life? ›

Origin of life means the appearance of simplest primordial life from non- living matter. Evolution of life means the gradual formation of complex organisms from simpler ones.

What do you mean by origin of life explain the origin of new species? ›

Answer: Abiogenesis, or informally the origin of life, is the natural process by which life has arisen from non-living matter, such as simple organic compounds. ... Many approaches to abiogenesis investigate how self-replicating molecules, or their components, came into existence.

What is the most accepted theory about the origin of life and why? ›

Darwin's theory of evolution by natural selection opened the way for the modern view of the origin of life (see FAMOUS GEOLOGISTS | Darwin). In Darwin's theory there is not necessarily a ladder of progress from simple to more complex forms. Simple organisms can be as evolutionarily successful as complex ones.

Which theory best explain the origin of Earth? ›

Nebular Hypothesis of Earth's Origin

The nebular hypothesis is the theory that refers to the spinning clouds of dust that are made of light elements.

How did all life begin? ›

Many scientists believe that RNA, or something similar to RNA, was the first molecule on Earth to self-replicate and begin the process of evolution that led to more advanced forms of life, including human beings.

What is the importance of theories? ›

Theories are vital: They guide and give meaning to what we see. When a researcher investigates and collects information through observation, the investigator needs a clear idea of what information is important to collect. Thus, valid theories are validated by research and are a sound basis for practical action.

What is the purpose of a theory? ›

Theories are formulated to explain, predict, and understand phenomena and, in many cases, to challenge and extend existing knowledge within the limits of critical bounding assumptions. The theoretical framework is the structure that can hold or support a theory of a research study.

What is theory explain the definition with examples? ›

The definition of a theory is an idea to explain something, or a set of guiding principles. Einstein's ideas about relativity are an example of the theory of relativity. The scientific principles of evolution that are used to explain human life are an example of the theory of evolution.

What is the origin of theory? ›

The English word theory derives from a technical term in philosophy in Ancient Greek.

Who proposed theory of origin? ›

Oparin and Haldane proposed theory of origin of life.

Where did the first life originated? ›

So, the correct answer is 'In water'

Do you think it is important for us to understand the origins of the universe? ›

Knowing about our cosmic origins helps us understand how we came to be as well as how we might impact the universe now and in the future. This “big picture” thinking has led to many important discoveries and a greater understanding of how the universe works, including our tiny corner of it.

How did humans explain the origin of the universe? ›

The most widely accepted explanation is the big bang theory. Learn about the explosion that started it all and how the universe grew from the size of an atom to encompass everything in existence today.

Is evolution a theory or fact? ›

Evolution is only a theory. It is not a fact or a scientific law. Many people learned in elementary school that a theory falls in the middle of a hierarchy of certainty—above a mere hypothesis but below a law. Scientists do not use the terms that way, however.

How does science explain the origin of life? ›

Darwin's theory of biological evolution tells us that all life on earth may have originated from a single, relatively simple reproducing creature living in the distant past. This idea is based on many observations, one of which is that when living things reproduce, children are often born with random new traits.

What was the first form of life? ›

The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old. The signals consisted of a type of carbon molecule that is produced by living things.

How was life born? ›

Most experts agree that all life today evolved by common descent from a single primitive lifeform. It is not known how this early life form evolved, but scientists think it was a natural process which happened about 3,900 million years ago.

What is the purpose of life on earth? ›

All life forms share at least one essential purpose: survival. This is even more important than another key purpose for life, reproduction. Plenty of organisms, after all, are alive but do not reproduce.

How many theories are there about how the earth was created? ›

There are two theories explaining the formation of the Earth: This first one is the core accretion model. This model suggested that before the formation of the Earth, the solar system was a cloud of dust and gas known as solar nebula.

Who was the first human on Earth? ›

Homo sapiens, the first modern humans, evolved from their early hominid predecessors between 200,000 and 300,000 years ago. They developed a capacity for language about 50,000 years ago. The first modern humans began moving outside of Africa starting about 70,000-100,000 years ago.

When did humans start? ›

The first humans emerged in Africa around two million years ago, long before the modern humans known as Homo sapiens appeared on the same continent. There's a lot anthropologists still don't know about how different groups of humans interacted and mated with each other over this long stretch of prehistory.

When did human life begin on Earth? ›

It took 13.8 billion years of cosmic history for the first human beings to arise, and we did so relatively recently: just 300,000 years ago.

What are the different theories about origin of life class 10? ›

In the year 1953, Oparin and Haldane suggested that life originated from non-living organic molecules like proteins and RNA. This was followed by the theory of chemical evolution which suggested that atmospheric conditions of the earth led to the formation of organic molecules from inorganic molecules.

How does the Panspermia theory explain the origin of life? ›

The extraterrestrial or panspermia theories suggest that life existed in outer space and was transported by meteorites, asteroids, or comets to a receptive Earth. In this case the origin of life is not related to environments possible on the early Earth.

What is the modern theories on the origin of the universe? ›

The most widely accepted explanation is the big bang theory. Learn about the explosion that started it all and how the universe grew from the size of an atom to encompass everything in existence today.

How did life first begin on Earth? ›

It seems possible that the origin of life on the Earth's surface could have been first prevented by an enormous flux of impacting comets and asteroids, then a much less intense rain of comets may have deposited the very materials that allowed life to form some 3.5 - 3.8 billion years ago.

Who proposed the origin of life concept? ›

The idea that all life on Earth has a common origin became well established only in the twentieth century. Early ideas on the evolution of life were most clearly expressed by Lamarck, who described the process as one of progression from simpler to more complex and advanced forms (see EVOLUTION).

What do you mean by origin of life explain the origin of new species? ›

Answer: Abiogenesis, or informally the origin of life, is the natural process by which life has arisen from non-living matter, such as simple organic compounds. ... Many approaches to abiogenesis investigate how self-replicating molecules, or their components, came into existence.

Why do we need to trace back the origin of life? ›

Consequently, studying the origin and earliest evolution of life, along with the long-term evolution of the Earth's environments, helps us understand why the Earth became habitable and why terrestrial life has persisted for billions of years.

What is Oparin Haldane theory? ›

The Oparin-Haldane hypothesis suggests that life arose gradually from inorganic molecules, with “building blocks” like amino acids forming first and then combining to make complex polymers.

What is the best definition of panspermia? ›

/pænˈspɜː.mi.ə/ the theory that very small organisms or chemicals that begin life can be found everywhere in the universe and that they made life on earth begin: The theory of panspermia - germs or spores spreading life through the universe - was touted by the late Nobel laureate Francis Crick.

Which is the latest theory of origin of the earth? ›

The most widely accepted modern theory regarding the origin of the earth is the “Big Bang Theory”. It shows how the universe grows from an atom-sized point by which the whole universe lies.

What is the real origin of the universe? ›

The Big Bang was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded. Most astronomers use the Big Bang theory to explain how the universe began.

What is the beliefs about the origin of the universe? ›

The current scientific thinking about the creation of the world is that it was caused by the Big Bang. This claims that all matter was originally concentrated into a tiny point which, as a result of a massive explosion in space 13.7 billion years ago, expanded into the universe and is still expanding today.

Who was the first human on Earth? ›

Homo sapiens, the first modern humans, evolved from their early hominid predecessors between 200,000 and 300,000 years ago. They developed a capacity for language about 50,000 years ago. The first modern humans began moving outside of Africa starting about 70,000-100,000 years ago.

When did life start? ›

The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old.

Who was the first person to live on Earth? ›

Adam is the name given in Genesis 1-5 to the first human. Beyond its use as the name of the first man, adam is also used in the Bible as a pronoun, individually as "a human" and in a collective sense as "mankind".

Videos

1. Origin of Life
(William Soriano)
2. Top 3 Theories on the Origin of Life
(Top 3)
3. New Theories on the Origin of Life with Dr. Eric Smith
(The Aspen Institute)
4. THEORIES OF ORIGIN OF LIFE
(POONAM YADAV Botany)
5. Earth and Life Science Rewind 7 Experiments and Theories on the Origin of Life
(Sensei Gian)
6. The mysterious origins of life on Earth - Luka Seamus Wright
(TED-Ed)

Top Articles

You might also like

Latest Posts

Article information

Author: Ouida Strosin DO

Last Updated: 11/27/2022

Views: 5537

Rating: 4.6 / 5 (76 voted)

Reviews: 91% of readers found this page helpful

Author information

Name: Ouida Strosin DO

Birthday: 1995-04-27

Address: Suite 927 930 Kilback Radial, Candidaville, TN 87795

Phone: +8561498978366

Job: Legacy Manufacturing Specialist

Hobby: Singing, Mountain biking, Water sports, Water sports, Taxidermy, Polo, Pet

Introduction: My name is Ouida Strosin DO, I am a precious, combative, spotless, modern, spotless, beautiful, precious person who loves writing and wants to share my knowledge and understanding with you.